Anisakiasis and vanishing tumor of the cecum

There have been few reports to date of vanishing gastric tumors caused by anisakiasis [1]. The large intestine is rarely affected because the ingested larvae usually do not travel that far down the gastrointestinal tract. Colonic anisakiasis occasionally resembles a colonic tumor, because it leads to edema, acute phlegmonous inflammation, or the formation of granulomas around the larvae in the submucosa of the intestinal wall [2].

A 77-year-old man attended our hospital for a positive fecal occult blood test. He was asymptomatic. He had a history of appendectomy for acute appendicitis at the age of 19 and ate raw fish almost every day. His white blood cell count was normal with no eosinophilia. At colonoscopy, a clearly demarcated, depressed lesion with raised margins (similar to a Borrmann type 2 lesion) was identified in the cecum ([Fig. 1]).

Fig. 1 Colonoscopy showing a lesion in the cecum, similar to a Borrmann type 2 lesion.

The histopathological examination of the biopsy specimens revealed eosinophilic infiltration of the lamina propria mucosae and the submucosa, and necrosis of the epithelium ([Fig. 2]).

Fig. 2 Histopathological section of the biopsy specimen showing eosinophilic infiltration in the lamina propria mucosae and necrosis of the epithelium.

Malignant cells were not seen. Computed tomography showed wall thickening in the cecum ([Fig. 3]).

Fig. 3 Computed tomography scan showing cecal wall thickening and the “dirty fat” sign around the lesion.

On repeat colonoscopy after 16 days, the tumour resembling a Borrmann type 2 lesion had disappeared and a reddish scar with small erosion was seen in the cecum ([Fig. 4]).

Fig. 4 Repeat colonoscopy showing disappearance of the tumor and a reddish scar with a small erosion in the cecum.

Serum titers of both IgG and IgA antibodies to Anisakis larvae on the day of the second colonoscopy were slightly elevated at 1.61 (cut-off index, normal < 1.50). At another colonoscopy a year later, the tumor had completely disappeared and a whitish scar was seen in the cecum ([Fig. 5]).

Fig. 5 Colonoscopy after a year showing a whitish scar but no evidence of tumor.

The vanishing tumor may be considered to be anisakiasis of the cecum.

Endoscopy_UCTN_Code_CCL_1AD_2AZ

References

• 1 Takeuchi K, Hanai H, Iida T. et al . A bleeding gastric ulcer on a vanishing tumor caused by anisakiasis.  Gastrointest Endosc. 2000;  52 549-551
• 2 Verhamme M A, Ramboer C H. Anisakasis caused by herring in vinegar: a little known medical problem.  Gut. 1988;  29 843-847